JPH0119161Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an illumination device for removing electric charge remaining on the photoreceptor drum of an electrostatic copying machine, and in particular, such a lighting device for an electrostatic copying machine capable of making copies of multiple sizes. This relates to improvements in equipment.

In an electrostatic copying machine, as shown in Figure 1,
The original 1 is irradiated with light from a lamp 2, and the reflected light is guided to the photoreceptor drum 3 to form a charged pattern on the drum 3 in the shape of the image on the original 1, and then the charged portion is Powdered toner 5 is attached by the magnetic brush 4, and transfer paper 7 is sequentially sent out from the paper feed tray 6, charged, and then run close to the photosensitive drum, at which time the transfer is transferred from the drum to the transfer paper. will be carried out.

In order to obtain a clear copy in the above process, the toner remaining on the photosensitive drum 3 is removed after the transfer is performed, but this residual toner is usually removed by a light projecting means. 8
The residual charge on the drum is first removed by light irradiation from the drum, and then by the rotating brush 9 wiping the drum surface.

Incidentally, in the electrostatic copying machine described above, since the width range of the charged portion of the photoreceptor drum 3 is varied according to the copy size, the light emitted from the light projecting means is also divided into parts corresponding to the width range. It is desirable to do so.

This is mainly to minimize power consumption for removing residual charges. As shown in FIG. 2, a conventional illumination device suitable for this purpose has reflective frames 11 partitioned according to each copy size stacked on a printed circuit board 10, and each segment A, B, C, Generally, lamps 12 are installed in D, C', B', and A', and a light diffusion filter 13 is installed between the lamps 12 and the photosensitive drum 3.

The conventional example shown in Fig. 2 is designed to accommodate four types of copy sizes: (1) segment (D);
(2) Segment (C+D+C') (3) Segment (B+
C+D+C'+B') (4) Segment (A+B+C+D
+C'+B'+A'), the lamps 12 in each segment are turned on, and a predetermined zone of the photoreceptor drum 3 is irradiated. however,
In such conventional examples, the copy size rating (e.g.
A3-5 size, B3-5 size, etc.), it is impossible to make the size (width length) of each segment a simple integer ratio. (The rated one is used.) The irradiation range of each photoreceptor drum 3 is different. Incidentally, it is desirable that the light irradiated onto the photoreceptor drum 3 be uniform and at the weakest level within the range that can completely remove residual toner.

This is because the photoelectric material such as selenium coating the photoreceptor drum becomes fatigued depending on the intensity of the irradiated light. For this reason, in the conventional example, the irradiation light is made uniform by making the light transmittance of the light diffusion filter 13 uneven.
As shown in FIG. 3, there is a natural limit to the uniformity of the irradiated light that can be obtained by such means, and
Due to the light absorption of the light diffusion filter 13, the irradiation light (above) exceeds the required level ₀ (Fig. 3).
It has disadvantages such as requiring a lot of electricity to obtain the desired amount of power. This invention was made to eliminate the above-mentioned drawbacks of the conventional example, and uses prisms of different shapes to efficiently transmit light from lamps distributed in blocks according to the copy size with less loss. It is an object of the present invention to provide an illumination device for erasing residual charges, which guides residual charges to a photoreceptor drum and prevents uneven brightness from occurring on the photoreceptor drum.

Hereinafter, the present invention will be described with reference to drawings showing embodiments of the present invention.

Reference numeral 20 denotes an exterior case of the device of the present invention, which includes seven rooms separated by a partition wall 20a, and light emission windows 20A and 20B provided for each room and arranged in a line on the front side (on the side of the photoreceptor drum 3). ,20C,20
D, 20C', 20B', 20A' (these windows, singly or in combination, form a light emitting segment corresponding to the copy size). 2
Reference numerals 1 to 24 denote block-shaped prisms made of a resin with good light transmittance such as acrylic or polycarbonate, and each room of the exterior case 20 has slopes (light emitting surfaces) 21a to 24a. ,
It is inserted and fixed so as to face each of the windows 20A to 20A'. The bottom surfaces 21b to 24b of the prism are subjected to a roughening treatment (preferably, a hairline roughening treatment along the direction perpendicular to the paper plane of FIGS. 5-2 to 8-2), and Lamp storage holes 21c to 24c are provided on the surface facing the slope.

In addition, a particularly long prism 24 (Fig. 8-1) has a plurality of lamp storage holes 2 along its longitudinal direction.
4c is provided, and the lamp storage hole 24
Slopes 24d to 24g are provided on both sides of c.

The slopes 21a to 24 of each prism 21 to 24
The angle between a and the rough surfaces (bottom surfaces) 21b to 24b differs depending on the width of each prism and the number of lamps 25 set in each prism.
(Figures 5-2 to 8-2) The lamp 25 is installed on a printed wiring board 26, and the printed wiring board is attached to the outer case 2.
When fixed at 0, it is inserted into the lamp storage hole of each prism. 27 is the rough surface 21 of each prism.
b to 24b, and 28 fills the gap between the reflective sheet 27 and the bottom surface of the exterior case 20, which is caused by the difference in the shape of each prism, and attaches each prism etc. to the exterior case. It is a fixing means for fixing.

The lighting device of the present invention is composed of the above-mentioned parts, so when the lamp 25 is turned on now, the light from the lamp flows into the inside of each prism 21-24 from the wall of each lamp storage hole 21c-24c. The incident light is repeatedly refracted and reflected by the inside of each prism, the outer case 20, and the reflective sheet 27, and in the end, most of the incident light becomes the slope 21a of the prism.
24a and the light emitting windows 20A to 20A'.

The intensity of the emitted light is then almost uniform over the entire area of each light emitting segment (ie, each prism slope 21a-24a in each window 20A-20A').

This is due to the effect of the difference in the shape of each prism, the hairline roughening treatment, and the reflective sheet 27.
This is due to the (reflection) effect of the exterior case 20. This point will be explained below. Of the light incident on the prism, only a small amount is directly emitted to the outside through the slope, and most of it is refracted and reflected multiple times inside the prism, the reflective sheet 27, the printed circuit board 26, and the exterior case 20. After repeating this, that is, at least once, the light passes through the bottom surface (rough surface) of the prism to the light emission windows 20A to 20A'. By the way, when the roughening treatment on the bottom surface of the prism has directionality (for example, when the surface is roughened in a hairline shape as described above), the roughened surface is parallel to the direction of the roughening. Most of the incident light passes through the rough surface, is reflected by the reflective sheet 27, and passes through the rough surface again, or travels through repeated reflections between the two and is diffused along the direction of the roughness. However, on the other hand, a considerable portion of light incident on the rough surface perpendicular to the direction of the roughness is scattered and reflected and directed upward. Therefore, especially when many surfaces of the prism are closed by reflective systems as in the present invention, the incident light is efficiently diffused along the direction of the roughness, and therefore the light emitting window 20A There is a remarkable tendency for the intensity of emitted light from ~20 A' to become uniform along its longitudinal direction. Even when there is no directionality in roughening the back surfaces 20b to 24b, the incident light is transmitted through the light emission windows 20A to 20.
By repeating refraction and reflection until reaching A',
This effect is achieved to some extent. Moreover, the slopes 20a to 24a of the prism and the back surfaces (rough surfaces) 20b to 2
4b facing each other, when other conditions are the same, the intensity of the emitted light from the light emission window (per unit area) is equal to the opposing angle of both sides (in this example, the 5th - (as shown in Figures 2 to 8-2). By utilizing this property, it is possible to eliminate the difference in the intensity of the light emitted from each of the light emitting segments.
(Fig. 11) Incidentally, the emitted light naturally becomes weak between the light emitting segments, that is, at the partition wall 20a, but in order to weaken this tendency, for example, as shown in Fig. 10, both sides of the tip of the partition wall 20a are It may have a cut shape.

As described above, if the illumination device of the present invention is used, the intensity of the emitted light from the light emitting segments that function in selective combination can be adjusted depending on the copy size, depending on the width of the segments. Regardless of the situation, using lamps of the same rating,
Since the charge can be kept constant and uniform over the entire longitudinal direction, the charge remaining on the circumferential surface of the photoreceptor drum of the copying machine can always be kept to the minimum necessary level, regardless of the difference in copy size. light of strength
It is possible to uniformly remove toner with irradiation light L (FIG. 11) at a level close to L ₀ and toner can be removed evenly, making it possible to always obtain clear copies.

Furthermore, the above method makes it possible to minimize the fatigue of the photoelectric material on the photoreceptor drum, and in addition, compared to conventional methods, lamp light is used more efficiently, so the required power consumption is minimized. It can be held down.

In the above embodiment, in order to reduce light loss, the entire surface of each prism except for the portions corresponding to the light emitting windows in the slopes 21a to 24a, the bottom surfaces 21b to 24b, and the wall surfaces of the lamp storage holes 21c to 24c. A specular reflection treatment (for example, aluminum vapor deposition, etc.) may be applied to the surface.

The shape etc. of each prism can also be changed as appropriate.

[Brief explanation of the drawing]

Figure 1 is a diagram that simply shows only the main parts of a copying machine. Figure 2 is an explanatory diagram of a conventional illumination device for removing residual charges. The diagram shown in FIG. 4 is an overall perspective view of the illumination device for removing residual charge of the present invention, and FIGS. 5-1 and 6-
1, 7-1, and 8-1 are perspective views of the prism used in the fourth illustrated embodiment, and FIGS. 5-2 and 6.
Figures -2, 7-2, and 8-2 are cross-sectional views of each of the above prisms, and Figure 9 is a cross-sectional view of the embodiment shown in Figure 4.
FIG. 10 is a partially enlarged view of the embodiment in FIG. 4, and FIG.
The figure is a diagram showing the intensity of light emitted by the illumination device of FIG. 4. 1... Original, 2... Lamp, 3... Photosensitive drum, 4... Magnetic brush, 5... Powder toner, 6...
...Paper feed tray, 7...Transfer machine, 8...Light projecting means,
9... Rotating brush, 10... Printed wiring board, 1
1...Reflection frame, 12...Lamp, 13...Light diffusion filter, 20...Exterior case, 20A-20
A'...Light emission window, 20a...Partition wall, 21-24
...Prism, 21a-24a...Slope, 21b
~24b...bottom surface, 21c~24c...lamp storage hole, 25...lamp, 26...printed wiring board, 27...diffuse reflection sheet, 28...fixing means.

Claims (1)

[Claims for Utility Model Registration] Made of a resin with good light transmittance, it has a lamp storage hole that introduces light from the lamp, and a roughened surface that scatters and reflects the light from the lamp stored in the storage hole. A bottom surface, a reflective sheet provided along the bottom surface, and a light emitting slope arranged at a light incident angle so as to transmit light from the bottom direction while reflecting light from the lamp direction. , a lighting device for erasing residual charge in a copying machine, characterized in that a plurality of prisms having a substantially uniform surface distribution of emitted light from the light emitting slopes are arranged so that the light emitting slopes are lined up in a row. Device.